In the past, numerous attempts have been made to design plastic containers for food and other consumable products which include a plastic closure cap for the container having a tear strip which must be removed the first time the container is opened, thereby providing security against adulteration or contamination of the product. Generally, such container closure caps are designed for reuse, so that once the tear strip is removed, the cap still operates effectively to reclose the container.
A very effective reclosable container with a tamper indicator is illustrated by U.S. Pat. No. 4,682,706 to F. DeVore et al., which is assigned to the assignee of the present application. Here, the tear off strip for the container closure has a plurality of spaced apart grooves defined in the surface thereof which are covered by a web so that the tear off strip outer member appears smooth. The web over each groove is adapted to break when a relatively small force is applied at any location along the tear off strip between the grooves to indicate that the assembly has been tampered with. Once the tear off strip is removed, the closure member is reusable and is retained on the container by a central section which is inserted into the container and engages the container inner wall combined with a small portion of the closure which remains to engage the container outer wall.
In reclosable containers having tear strips, this use of a cap configuration wherein a portion of the cap extends into the container to engage the inner wall of the container and cooperate with an outer portion of the cap remaining after the removal of a tear strip is quite common, as illustrated by U.S. Pat. Nos. 2,998,158 to E. S. Tupper, U.S. Pat. No. 3,356,250 to N. E. Russell, U.S. Pat. No. 3,557,998 to S. D. Collie, and U.S. Pat. No. 4,660,735 to P. Peschardt et al. All of these patents illustrate such reclosable cap structures wherein, once a tear strip is removed, the cap may be remounted on a container and held in place by engagement between portions of the cap and the inner and outer wall of the container.
For some plastic and paperboard containers, it is not desirable to provide a container closure cap having a portion of the cap which extends downwardly in engagement with the inner wall of the container. This, for example, might be true of ice cream containers where the container lid or cap is positioned above a membrane sealed to the upper lip of the container and extending across the container contents. It is extremely desirable to close such containers with a tamper indicating cap having a tear strip, and it is also desirable to be able to tightly reclose these containers once the tear strip has been removed. However, this reclosure cannot be accomplished by engagement between the cap and both the inner and outer surfaces of the container.